You will sometimes hear the word 'riposte' used in this context, although the idea behind a riposte is the speed and cleverness of the reply, rather than the forcefulness of the reply.
It's a word borrowed from the sport of fencing, where it's a quick return thrust after you parry (block) your opponent's attack. The idea carries over to verbal sparring.
Although it's not quite the same idea as 'counterblast', I suspect it's much more widely understood.